GM CV owners
- Thread starter billg27
- Start date
paullud
Veteran Expediter
I've got 100,000 on my last set. Looking at that photo makes me think it wouldn't be a bad idea to have a look-see. It runs all right at the moment but Winter is coming and a spark plug that looks like those won't help cold starts.
Last year, in August, I had to have everything changed. The plugs were terrible, the wires were--- you really don't want to know, the distributor cap had seen better days and the rotor needed replacement too. That's the way it was when I bought it, it gave me a couple of weeks and then started running rough. It needed fuel-injector cleaner, as it turned out, but the ignition system wasn't doing it any good. It runs like a champ right now.
Last year, in August, I had to have everything changed. The plugs were terrible, the wires were--- you really don't want to know, the distributor cap had seen better days and the rotor needed replacement too. That's the way it was when I bought it, it gave me a couple of weeks and then started running rough. It needed fuel-injector cleaner, as it turned out, but the ignition system wasn't doing it any good. It runs like a champ right now.
wvcourier
Expert Expediter
I have an 04 2500 4.8, does anyone know how to get to the fuel filter? Ive not been getting good mpg, and was going to replace fuel filter, but autozone is telling me that its not serviceable, so they dont make or sale them?? Is this normal? Wat kind of preventive maintance should i do, so injectors dont get messed up, and to get better mpg?
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wvcourier
Expert Expediter
I replaced my plugs and wires when my altenator and water pump went out(about 2800 miles ago) but didnt see an improvement in mpg..and when i had to get front wheel hubs replaced a few weeks ago, i had them do a front end alighnment...thought that might help, but it hasnt....so looks like my next repair will be a Fuel Pump.
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In my gas vehicles I run Autolite Platnum if you have a distributor cap and rotor spend the extra fifteen or twenty bucks and buy the carquest or nappa premium caps and rotors with brass guts, they last longer and give a better spark. I pull, inspect and clean the distributor, cap, and rotor, I use brake cleaner and a soft brush on the cap and rotor and regap the plugs every other oil change in my personal drivers to clean inspect and regap them and plan to do the same at least a couple times a year on the C van at least twice a year. Besides, do you want to buy a top end rebuild when they cant remove the plugs or they shear off? Blow the dust and crud out of the distributor and spray the inside of the with a good silicone spray I use C.R.C.
As for the fuel filters injectors? Have a mechanic or you can install an inline fuel filter if you have the know how. Just make sure the filter and fittings are ment for fuel injection and are the prpoer size and flow rate. You might have one allong the frame rail just follow the fuel line. Other than using a decent quality fuel I run Berrymans B 12 Chemtool every 10 or 15 fills seems to keep the injectors and plugs happy.
Good luck
Bob Wolf
As for the fuel filters injectors? Have a mechanic or you can install an inline fuel filter if you have the know how. Just make sure the filter and fittings are ment for fuel injection and are the prpoer size and flow rate. You might have one allong the frame rail just follow the fuel line. Other than using a decent quality fuel I run Berrymans B 12 Chemtool every 10 or 15 fills seems to keep the injectors and plugs happy.
Good luck
Bob Wolf
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Not getting good mpg compared to what, the mpg you got 5 months ago or others mpg? You need a baseline to make a meaningful comparison. If you were getting 16 mpg 5 months ago and are now getting 14 mpg, then you have a problem. Could be something simple like an air filter, mass air flow sensor, etc. It ain't the fuel filter or pump.
Don't waste your money replacing a fuel pump to improve your fuel mileage. Either the pump is working or it isn't. The pump and filter will have no effect on fuel economy. I have 627,000 miles on the original fuel pump. The fuel filter is an integrated part of the pump. If you can't find a filter in the fuel line running along the left frame rail, then it is integrated with the pump in the tank.
If you really want to improve your fuel mileage, slow down, don't idle and ease down on the gas pedal when accelerating.
Moot, your exactly right. The fuel pump either works or doesn't. If the filter was partly plugged, you would get some surging when accelerating or when running high speeds or climbing long inclines. I won't spend the $500 - $700 for the pump and labor until it stops running. I will be doing spark plugs, wires, cap and rotor before winter. Hopefully that will help with easier cold starts and I'm hoping for a little better milage.
wvcourier
Expert Expediter
627,000, thats impressive, but im sure thats an exception and not the rule...my baseline is the average for the 4.8 engine..its below average by about mpg..ive had the van for six months, and have put about 45,000 more miles on engine(just over 200,000 miles) and would rather be safe then sorry..when my tank gets low, it starts surging and making funny sounds, but only when i let fuel get low...i would rather be safe then sorry..ive replaced air filter, and i never speed, my guess is its the fuel injectors or fuel pump...but idk...ill spend the 300 for the fuel pump, and local mechanic will put it in for 100 dollars...
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Where did you the average miles per gallon number for the 4.8L engine from? Was this an EPA estimate or actual real world fuel mileage? Was this 4.8 engine in a 2500 van or a Malibu? What exactly was that mpg number and what is yours?
Again, compared to what? How low is low? I could tell you about my reduced fuel mileage, uneven tread wear and a funny whop whop sound my tires make, but only when I let the air pressure get low.
While you may need a new fuel pump, replacing it will not increase your fuel mileage. $400 is a good price for a fuel pump replacement. Does your mechanic realize replacing the pump involves dropping the fuel tank?
Good luck and keep us updated.
purgoose10
Veteran Expediter
Check inside the frame rail on the drivers side (follow the fuel line) and see if your chevy has an inline gas filter. Some do, some don't. Mine does. Change it. Most people don't bother with them but using ethynol you should change them at least every 6mo's. They are about $25 bucks, pretty pricey but that's Chevy's price. Like the others say the fuel pump ether works or it doesn't.
Ethynol will clog a filter.
I might also ad that it is under a metal cover that's a real pain to get at. Another reason people don't change them.
They also make a Ethynol neutralizer that is sold at Home depot, Tractor supply and others. Use it, great stuff. I don't buy ethynal gas when I'm home and also always ad Lugas gas and fuel treatment to every tank.
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I was trying to figure out how a bad fuel pump/filter would cause a vehicle to burn more gas. I'm stumped on that one. A plugging filter will cause surging, and a bad fuel pump will fail completely to deliver gas, but neither of these will cause your van to burn more fuel than it ordinarily should. I'd be looking for other problems. How about brakes? A dragging brake will cause increased fuel use. Low tires will do it, too. Front-end alignment, if something isn't right it could increase drag and burn more fuel. A vacuum leak causes all sorts of problems, it's worth a check. Last but not least, asking too small an engine to do too big of a job will burn gas. That 4.8 already has its job cut out for it just dragging a full-size van around, now you want to load it with freight and ask it to do highway miles in hilly country-- and you don't expect it to burn some fuel??? Last time I was in West Virginia, I couldn't help noticing it isn't exactly flat land.
purgoose10
Veteran Expediter
A paper gas filter using ethynol gas has a white fatty looking substance in it. For fuel injected engines proper pressure is required for performance. A dirty filter reduces that pressure. It does not stick to metal so it doesn't hurt the pump. If you look at a small engine like a trimmer or similar if it's been used for a season look at the plastic lines. They will be white. Pull a line off and it looks just like a clogged artery in a human.
I searched a long time to find a 3500, power everything, tow package, not white and with a 4.8 engine. The engine is not as underpowered as you think. On my worst tanks, I still get better milage then the older 6.0 with the 4 speed trans on their best days. On my worst tanks with hills and strong winds, I can still get 16+ and I run fast, even in those conditions. I have never found a hill or mountain that it wouldn't climb at full speed. Yes, it downshifts more often, but it does the job. It had 285 hp, what does a Sprinter have? The 6.0 is 330 hp. Not that different unless your drag racing. I can go 450+ miles on a tank of fuel, most 6.0 are fueling at 300 - 325 miles. I have carried 3,000 lbs through the Rocky Mountains and for some unknown reason, with their 85 octane fuel, I can pull 18+ mpg in the mountains. All of my best milage tanks have been with the low octane fuel and in the mountains. ???? If I get a new CV I will purchase the 4.8 again. I'm not racing, I just need it to be dependable and get me there as efficiently as possible.